docs: async def ack(self, tube, task_id):
          """
          Report task successful execution.
  
          Ack is accepted only from the consumer, which took the task
          for execution. If a consumer disconnects, all tasks taken
          by this consumer are put back to READY state (released).
  
          Returns tarantool tuple object.
          """
          cmd = tube.cmd("ack")
          args = (task_id,)
  
          res = await self.tnt.call(cmd, args)
          return res